This will be helpful to some. I make helper functions to estimate sin and cos functions. I used Taylor series to estimate. Here's an example drawing a dot at the position of the crank:

on draw do
// Draw a crank dot
if event.ra!=0 then
a = event.aa
a /= 180
a *= 3.14159
emit "sin"
emit "cos"
x = sin
x *= 32
x += 32
x += 2
y = cos
y *= 32
y += 32
y += 2
end
fill "white" at x,y,4,4
end

Put this in the game script:

on sin do
aNorm = a
while aNorm>=3.141592 do
aNorm -= 6.283184
end
n = 0
modifier = 1
sin = 0
while n<6 do
// modifier * aNorm^(2n+1)
// -------------------
// (2n+1)!
pow = n
pow *= 2
pow += 1
// numerator
num = modifier
p = pow
while p>0 do
num *= aNorm
p--
end
// denominator
f = pow
den = 1
while f>0 do
den *= f
f--
end
if den==0 then
den = 1
end
// log "{modifier} * {num}"
// log "------------------"
// log "{den}"
// Add to result
num /= den
sin += num
// Set up next loop
modifier *= -1
n += 1
end
end
on cos do
oldA = a
oldSin = sin
a += 1.57079
call "sin"
cos = sin
cos *= -1 // Trig is y up, pulp is y down
a = oldA
sin = oldSin
end

the n < 6 is the number of iterations, and I've found 6 is good enough for three decimal places.

Edit: There were some issues when the number was > pi, which I fixed by limiting the angle from -pi to pi.

How would we change where on the screen the crank dot appears?

The first snippet shows how to position the dot around a point, but doesn't explicitly say it.

on draw do
// Draw a crank dot
if event.ra!=0 then
a = event.aa
a /= 180
a *= 3.14159
emit "sin"
emit "cos"
x = sin
x *= 32 // Scale the radius 32 pixels wide
x += 32 // Move the center point 32 pixels to the right
x += 2
y = cos
y *= 32 // Scale the radius 32 pixels tall
y += 32 // Move the center 32 pixels down
y += 2
end
fill "white" at x,y,4,4
end

Yes, you could do your math to find where the x and y are, then divide each by 8 to convert to tile coordinates. Then use the goto function to send the player there.

x /= 8
x = floor x
y /= 8
y = floor y
goto x,y

Beware it might not be happy with you using the goto function in the draw event, so you might want to do the math in a regular event if this is your intended action.

Bit shaky but that works! I'll fiddle around with it as I go, but thanks very much for the help, this may have solved the problem I've been tussling with all day.

Instead of using emit to call these functions I would use tell event.game and call. emit has to ask the game, current room, player, and all 375 tiles in the current room if they handle the emitted event. That’s a lot more overhead than directly tell-ing the single object you already know implements the event handler. (And that overhead is only being compounded by calling it 20 frames per second in the draw event handler. I would move the sin/cos calculations and setting of x,y to the player’s crank event handler.)

@BoldBigflank A short followup: I’ve added native sine and cosine functions to PulpScript (plus tangent, radians, and degrees). One thing I noticed is that your pure PulpScript event handler versions are returning inverted values. So when you switch from these (the native versions provide a huge performance boost, PulpScript wasn't built to be especially math-y ) you’ll want to invert the new return values with *= -1. The additions should be up sometime this week. (I’ll update this comment when the changes go live.)